Autonomous robots rely on a variety of different sensor systems to obtain a rich, multi-modal representation of the environment. Haptic perception mainly depends on force sensors, which are available in many variants.
Force sensors either measure a force, a torque, or both force and torque (force and/or torque) vector at a single point, or a contact force distributed over a surface.
Force sensors that measure contact force profiles are often categorized as tactile sensors. In general, forces are kinesthetic data and not tactile data. Thus, the distinction between a force sensor and a tactile sensor is often not clear, which is why we use the generic term “haptic sensor”.
Force and/or torque sensors are usually installed between a robot arm and a tool (the end-effector) in order to measure the contact forces between a tool and the environment at a single point during grasping, manipulation tasks like mounting or placing of objects as well as gravitational and acceleration forces while moving objects.
Modern robots are also equipped with visual sensors, such as cameras. Cameras in the visual spectrum are the basic sensor for most computer vision algorithms such as object detection, visual search or pose estimation. An exemplary visuo-haptic sensor is disclosed in U.S. patent application publication 2016/0107316, published 21 Apr. 2016, the complete disclosure of which is herein incorporated by reference.